Post Bi-annual Maintenance Performance of Geregu Thermal Power Plant

Abstract

The continuous firing of a gas turbine engine make it become fouled with airborne contaminants like sand, dust, oil, salt and smoke which encrust the compressor and turbine components. Generally, the deterioration of axial flow compressors is a major cause of loss in gas turbine output and efficiency. The cleaning of the gas turbine compressor is the most effective method of preventing fouling. Cleaning maximises fuel efficiency, the life of the machine and recovers majority of lost power output. The most effective technique of cleaning the compressor and the air-filter of a gas turbine is the offline method. The technique includes injecting water into the compressor when the turbine is turned at cranking speed and requires the turbine to be shut down. This paper presents the performance evaluation of Geregu power plant gas turbine after a bi-annual maintenance operation. The performance parameters such as compressor pressure ratio, compressor discharge temperatures, turbine exit temperatures and power output improved significantly after the bi-annual maintenance operation. The generation utilization index increased from 0.55 to 0.90 andthe capacity utilization Index increased from 0.51 to 0.85 after the bi-annual maintenance operation. The station reliability index was 0.47 two months before the bi-annual maintenance operation but increased to 0.99 two months after maintenance, resulting to a total power generation increase from 66,000MWh two months prior to the biannual maintenance operation to 140,000MWh two months after the maintenance.